Question 1

Which of the following best describes a combustion reaction?

Accepted Answer

A reaction in which a hydrocarbon reacts with oxygen to produce carbon dioxide and water.

Question 2

Which of the following is the correct net ionic equation for the precipitation reaction between aqueous solutions of silver nitrate and sodium chloride?

Accepted Answer

$$\mathrm{Ag^+ (aq) + Cl^- (aq) \rightarrow AgCl (s)}$$

Question 3

A student mixes hydrochloric acid ($$\mathrm{HCl}) $$with sodium hydroxide ($$\mathrm{NaOH}) in a $$coffee-cup calorimeter. Which of the following statements is TRUE about this experiment?

Accepted Answer

The heat measured corresponds to the enthalpy change $$\Delta H of $$the reaction.

Question 4

Which of the following reactions is an example of a gas-evolution reaction?

Accepted Answer

$$\mathrm{Na_2CO_3 (aq) + 2HCl (aq) \rightarrow 2NaCl (aq) + H_2O (l) + CO_2$ (g)}$$

Question 5

Which of the following best describes a state function?

Accepted Answer

A property that depends only on the initial and final states, not on the path taken.

Question 6

A reaction occurs in a bomb calorimeter and releases 500 J of heat. What is the value of $$\Delta E$$ for the reaction?

Accepted Answer

$$\Delta E = -500\ \mathrm{J}$$

Question 7

Which of the following is the correct formula for calculating the heat absorbed by a solution in calorimetry?

Accepted Answer

$$q = m s \Delta T$$

Question 8

A gas expands from 2.0 L to 5.0 L against an external pressure of 1.0 atm. What is the work done by the gas (in Joules)? (Use $$1\ \mathrm{L \cdot atm} = 101.3\ \mathrm{J})$$

Accepted Answer

$$w = -303.9\ \mathrm{J}$$

Question 9

Which of the following statements about exothermic reactions is correct?

Accepted Answer

The enthalpy change $$\Delta H is $$negative and heat is released to the surroundings.

Question 10

Given the following reactions and their enthalpy changes:

$$\mathrm{C (s) + O_2$ (g) \rightarrow CO_2$ (g)}\ \Delta H = -393.5\ \mathrm{kJ}$$

$$\mathrm{2CO (g) + O_2$ (g) \rightarrow 2CO_2 (g)}\ \Delta H = -566.0\ \mathrm{kJ}$$

What is the enthalpy change for $$\mathrm{2C (s) + O_2$ (g) \rightarrow 2CO (g)}$$?

Accepted Answer

$$\Delta H = -221.0\ \mathrm{kJ}$$

Question 11

Which of the following is the correct molecular equation for the acid-base neutralization between sulfuric acid ($$\mathrm{H_2SO_4}) $$and potassium hydroxide ($$\mathrm{KOH}$$)?

Accepted Answer

$$\mathrm{H_2SO_4 (aq) + 2KOH (aq) \rightarrow 2H_2O (l) + K_2SO_4 (aq)}$$

Question 12

Which of the following is a correct net ionic equation for the reaction between aqueous hydrochloric acid and aqueous sodium hydroxide?

Accepted Answer

$$\mathrm{H^+ (aq) + OH^- (aq) \rightarrow H_2O (l)}$$

Question 13

A 50.0 g sample of water is heated from 25.0 $$^\circC to 75.0$$ $$^\circC. If $$the specific heat capacity of water is $$4.18\ \mathrm{J\ g$$^{-1}$$\ ^\circ C$$^{-1}$$}$$, how much heat is absorbed?

Accepted Answer

$$q = 10,450\ \mathrm{J}$$

Question 14

Which of the following is the correct formula for calculating the standard enthalpy change of a reaction using standard enthalpies of formation?

Accepted Answer

$$\Delta H^\circ_{rxn} = \sum n_p \Delta H^\circ_f (	ext{products}) - \sum n_r \Delta H^\circ_f (	ext{reactants})$$

Question 15

Which of the following is a redox (oxidation-reduction) reaction?

Accepted Answer

$$\mathrm{Zn (s) + Cu$$^{2+}$$ (aq) \rightarrow Zn$$^{2+}$$ (aq) + Cu (s)}$$

Question 16

A chemical reaction in a coffee-cup calorimeter causes the temperature of the solution to decrease. Which of the following is true?

Accepted Answer

The reaction is endothermic and $$\Delta H \u003e 0.$$

Question 17

Which of the following best describes Hess's Law?

Accepted Answer

The enthalpy change of a reaction is the same, no matter how many steps the reaction is carried out in.

Question 18

Which of the following is the correct total ionic equation for the reaction between aqueous sodium sulfate and barium chloride?

Accepted Answer

$$\mathrm{2Na^+ (aq) + SO_4$^{2-} (aq) + Ba$$^{2+}$$ (aq) + 2Cl^- (aq) \rightarrow $$BaSO_4$$ (s) + 2Na^+ (aq) + 2Cl^- (aq)}$$

Question 19

A 1.00 g sample of a fuel is combusted in a bomb calorimeter. The temperature of the calorimeter increases by 2.50 $$^\circC. If $$the heat capacity of the calorimeter is $$5.00\ \mathrm{kJ\ ^\circ C$$^{-1}$$}$$, what is the heat released per gram of fuel?

Accepted Answer

$$q = 12.5\ \mathrm{kJ\ g$$^{-1}$$}$$

Chapter 7 Exam

Guida di studio - Domande di pratica

Study guide - Flashcard